Using Reproductive Altruism to Evolve Multicellularity in Digital Organisms

Jack Hessel, Sherri Goings

Abstract

The processes by which multicellular organisms first emerged
from their unicellular ancestors are fundamental to the biology
of complex, differentiated life forms. Previous work suggests
that reproductive division of labor between specialized
germ and soma cells was central to this evolution in some
cases. Here, we assess the potential of the digital life platform
Avida to examine the trade-off between survival and replication
in multicellular organisms. Avida uses a grid of self-replicating
computer programs capable of mutation and evolution
to address biological questions computationally. We
model our digital organisms after the Volvocales, a flagellated
order of photosynthetic green algae that includes both unicellular
and multicellular species. We show that, given selective
pressures similar to those experienced by the Volvocales in
nature, digital organisms are capable of evolving multicellularity
within the Avida platform. The strategies we observed
that best handled the trade-off between survival and replication
involved germ cells producing sterile, somatic offspring.
These strategies are similar to those observed in volvocine algae,
which suggests that digital platforms, such as Avida, are
appropriate to use in the study of reproductive altruism.